#pragma once

#include <iostream>
#include <string>
#include <algorithm>
#include <jsoncpp/json/json.h>

#include "index.hpp"
#include "util.hpp"
#include "log.hpp"


namespace  ns_searcher
{
    struct InvertedElemPrint
    {
        uint64_t doc_id;
        std::vector<std::string> words;
        int weight;

        InvertedElemPrint():doc_id(0),weight(0){}
    };


    class Searcher
    {
    private:
        ns_index::Index *index; // 供系统进行查找的索引
    public:
        Searcher(){}
        ~Searcher(){}
    public:
        void InitSearcher(const std::string input)
        {
            // 1. 创建或者获取index对象
            index = ns_index::Index::GetInstance();
            LOG(INFO,"获取index单例成功...");
            // 2. 根据index对象创建索引
            index->BuildIndex(input);
            LOG(INFO,"建立正排和倒排索引成功...");

        }
        // query : 搜索关键字
        // json_string : 返回给用户浏览器的搜获结果
        void Search(const std::string query, std::string *json_string)
        {
            // 1. [分词]：对我们的query进行按照searcher的要求进行分词
            std::vector<std::string> words;
            ns_util::JiebaUtil::CutString(query, &words);
            // 2. [触发]：就是根据分词的各个“词”，进行index查找, 查找是忽略大小写的
            // ns_index::InvertedList inverted_list_all;
            std::vector<InvertedElemPrint> inverted_list_all;

            std::unordered_map<uint64_t, InvertedElemPrint> tokens_map;

            for(std::string word:words)
            {
                boost::to_lower(word);
                ns_index::InvertedList *inverted_list = index->GetInvertedList(word);
                if(nullptr == inverted_list)
                {
                    continue;
                }
                // inverted_list_all.insert(inverted_list_all.end(), inverted_list->begin(), inverted_list->end());
                for(auto elem : *inverted_list)
                {
                    auto &item = tokens_map[elem.doc_id];
                    item.doc_id = elem.doc_id;
                    item.weight += elem.weight;
                    item.words.push_back(elem.word);
                }
            }
            for(auto &item : tokens_map)
            {
                inverted_list_all.push_back(std::move(item.second));
            }
            // 3. [合并排序]：汇总查找结果，按照相关性（weight）进行降序排序
            std::sort(inverted_list_all.begin(), inverted_list_all.end(), \
                    [](const InvertedElemPrint &e1, const InvertedElemPrint &e2){
                        return e1.weight > e2.weight;
                    });
            // std::sort(inverted_list_all.begin(), inverted_list_all.end(), \
            //         [](const ns_index::InvertedElem &e1, const ns_index::InvertedElem &e2){
            //             return e1.weight > e2.weight;
            //         });
            // 4. [构建]：根据查找出来的结果，构建json串，  -----jsoncpp --- 通过Json完成序列化&&反序列化
            Json::Value root;
            for(auto item:inverted_list_all)
            {
                ns_index::DocInfo *doc = index->GetForwardIndex(item.doc_id);
                if(nullptr == doc)
                {
                    continue;
                }
                Json::Value elem;
                elem["title"] = doc->title;
                elem["desc"] = GetDesc(doc->content, item.words[0]);//TODO
                elem["url"] = doc->url;
                // for debug
                // elem["id"] = (int)item.doc_id;
                // elem["weight"] = item.weight;

                root.append(elem);
            }
            // Json::StyledWriter writer;
            Json::FastWriter writer;
            *json_string  = writer.write(root);
        }
        std::string GetDesc(const std::string &html_content, const std::string &word)
        {
            // 找到word在html_content中的首次出现，然后往前找50个字节（如果没有，到begin），往后找100个字节（如果没有吗，到end）
            // 截取这部分内容
            const int prev_step = 50;
            const int next_step = 100;
            // 1. 找到首次出现

            auto iter = std::search(html_content.begin(), html_content.end(), word.begin(), word.end(),[](int x, int y){
                return (std::tolower(x) == std::tolower(y));
            });
            if(iter == html_content.end())
            {
                return "None1!";
            }
            int pos = std::distance(html_content.begin(), iter);

            // int pos = html_content.find(word);
            // if(pos == std::string::npos)
            // {
            //     return "None1!";// 这种情况并不存在
            // }
            
            // 2. 获取start last
            int start = 0;
            int last = html_content.size()-1;
            if(pos-prev_step > start) start = pos-prev_step;
            if(pos+next_step < last) last = pos+next_step;

            // 3. 截取子串
            if(start >= last) return "None2!";
            return html_content.substr(start, last-start+1);
        }
    };
}